pheelicks

4 ms·

1.
by pheelicks 6mo ago
A5 - a pentagonal geospatial index: https://a5geo.org If you’ve used H3 the semantics should be familiar. The biggest differentiator is the fact that cells have exactly the same area globally, for why this matters see: https:&#
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Show HN: Starsalign.eu(starsalign.eu)
1 points by pheelicks 9mo ago|0 comments
3.
by pheelicks 11mo ago
Nice library. Without trying to start the classic geo-flamewar, do you consider returning the DD coordinates as [longitude, latitude]? This is in line with a number of formats out there, including the popular GeoJSON that is often used in J
4.
He rebuilt the world map using pentagons [video](youtube.com)
2 points by pheelicks 11mo ago|0 comments
5.
by pheelicks 11mo ago
It is a common misconception that h3 is equal area. At any resolution level the cell size varies by a factor of 2, which is (roughly) the same as S2. See the following visualizations for an illustration: https://a5geo.org/ex
6.
by pheelicks 11mo ago
Very impressive results, cool to see innovation in this space! I’d definitely be interested in a follow up post going into the details of the geometric algorithms. I’m working on my own DGGS, A5, the first (and only) to use pentagons. It of
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Optimal GeoParquet Partitioning Strategy(medium.com)
1 points by pheelicks 1y ago|0 comments
8.
by pheelicks 1y ago
This agrees with my experience on a project I’ve been working on this year, in particular related to porting the code. I’ve developed a strategy that I’m calling “Polyglot Mirroring” where the code is written in multiple languages at once,
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Ask HN: Polyglot Mirroring
1 points by pheelicks 1y ago|0 comments
10.
by pheelicks 1y ago
https://news.ycombinator.com/item?id=43971314 got some attention here, when I originally released the TypeScript version, so following up with the news that the library has now been entirely ported to Python. Not only is th
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A5 Geospatial Index(github.com)
2 points by pheelicks 1y ago|1 comments
12.
by pheelicks 1y ago
My mistake, you are correct. The base solid is indeed the rhombic dodecahedron. I believe the point about the angular defect is still valid though.
13.
by pheelicks 1y ago
Yes, such indices (S2 & H3) are widely used for providing a index in databases, so geospatial features that are close by in the world and stored in nearby databases rows. https://cloud.google.com/bigquery/docs/
14.
by pheelicks 1y ago
A5 cell boundaries are geodesics. One more difference that I thought of is that HEALPix is generally not aligned with the continents (makes sense as it is mostly used for astrophysics), whereas the hilbert curve used to index A5 is aligned
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by pheelicks 1y ago
If you're aggregating and comparing data across different locations for example: https://a5geo.org/examples/airbnb
16.
by pheelicks 1y ago
The base platonic solid that Healpix is based on is the octahedron ( https://en.wikipedia.org/wiki/Octahedron ), which A5 uses the dodecahedron( https://en.wikipedia.org/wiki/Regular_dodecahedron ). T
17.
by pheelicks 1y ago
Bear in mind that this is a "Show HN", the library was released just a few weeks ago! Whereas the other libraries have been around for a decade+ The plan is certainly to release versions in other languages, if you would like to be
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by pheelicks 1y ago
For a visual explanation of how the system works, as well as interactive examples, check out the project website at https://a5geo.org/examples/
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by pheelicks 1y ago
As a user, you generally don’t care about the math (and S2 is hardly simple either, as it warps the squares prior to projection). You just call the API and use the indices for spatial joins or computations. The primary benefit is indeed the
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by pheelicks 1y ago
Also check S2: http://s2geometry.io/ , created at Google before H3, which uses squares and underpins the fast indexing in BigQuery amongst many other things
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by pheelicks 1y ago
Yes, those are the obvious ones. This example: https://a5geo.org/examples/airbnb shows why the equal area is valuable in practice, while https://a5geo.org/examples/area shows the area variation vs
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Show HN: A5(github.com)
95 points by pheelicks 1y ago|29 comments
23.
by pheelicks 1y ago
The cells being the same shape is useful in some use cases and irrelevant in others. For example, see the Airbnb demo: https://a5geo.org/examples/airbnb . The H3 tiles are very different sizes in the two cities, and mak
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by pheelicks 1y ago
No, it is based on applying a lattice onto the faces of a dodecahedron (technically a pentakis dodecahedron). Take a look at https://a5geo.org/examples/teohedron-dodecahedron and other examples on the website. H3 is ba
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by pheelicks 1y ago
A pentagonal geospatial indexing system: https://a5geo.org/ If you’ve used H3 or S2 it should be familiar, the major difference (apart from the fact it uses pentagons) is that the cell areas are practically uniform, whereas
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A5: Like Uber's H3 but a bit weirder and more fun(simonwillison.net)
3 points by pheelicks 1y ago|0 comments
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by pheelicks 1y ago
Happy to share a project I've been working for the last few months: A5, a global, equal-area, millimeter-accurate geospatial index. If you you've come across S2 or H3 in the past, it has much in common, except that it uses pentago
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Show HN: A5 – A Pentagonal Spatial Indexing System(a5geo.org)
3 points by pheelicks 1y ago|1 comments
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Deck.gl v9 Released(deck.gl)
5 points by pheelicks 2y ago|0 comments
30.
by pheelicks 3y ago
Yes, I’ve tried it with the Eiffel Tower. You can see overhangs on the tv tower at the start of this demo https://3dtiles.carto.com/

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